1. Field of Invention
The present invention relates to an economic ISG (Idle Stop & Go) system, and more particularly, to a technology of implementing an ISG function at a low cost in a vehicle equipped with a common automatic transmission.
2. Description of Related Art
ISG systems improve fuel efficiency of vehicles by stopping the engine in idling, on the basis of information, such as the speed, the rotational speed of the engine, and the temperature of the cooling water when a vehicle stops.
In the related art, in order to achieve the ISG systems, an AGM (Absorptive Glass Mat) battery having charging and discharging durability, a battery sensor for estimating the states of the battery, a reinforcing starter for handling increase of the number of start times, a DC-DC converter for preventing an audio and a cluster from be reset by preventing voltage drop in restarting, and a brake boosting pressure sensor for preventing the engine from stopping under low boosting are generally needed and which are necessary parts for achieving all the ISG systems, regardless of the specifications of the transmissions of vehicles.
Further, a hill-start assist control device and a sub-oil pump are additionally required to achieve the ISG systems, when the transmission of a vehicle is an automatic transmission of the related art. The hill-start assist control device is provided to prevent a vehicle from moving back on a hill in restarting at the D-stage and the sub-oil pump is provided to maintain the hydraulic pressure of the automatic transmission, with the engine stopped.
However, additionally mounting the hill-start assist control device and the sub-oil pump in a vehicle may deteriorate the commercial quality of a vehicle, when the vehicle is a low-cost vehicle, because the number of parts and the cost increase.
The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.